Softness is an advantage for absorptive papers in many applications. For example, untreated paper tissues in contact with the skin, such as makeup removal tissues or paper handkerchiefs, can lead to reddening of the skin due to mechanical damage on frequent use, and indeed even to skin irritation.
Improved softness can be obtained by changing the paper tissue itself or by treating the fibers or the tissue with chemical substances. Polydimethylsiloxanes (silicones) are frequently used for treating the paper fibers or the paper tissue.
Owing to the hydrophobic nature of the polydimethylsiloxanes, the finishing of paper fibers or paper tissues leads to water repellent properties of the paper tissue. This is as a rule undesired since the ability of the tissue to rapidly absorb water is reduced.
Various methods for achieving a softening finish while retaining the hydrophilic properties are therefore described.
U.S. Pat. No. 5,538,595 describes the use of a two-component softener composition for paper, which comprises an ester-functional quaternary ammonium compound and organofunctional polyorganosiloxanes.
U.S. Pat. No. 6,054,020 discloses amino-modified polyorganosiloxane compounds and mixtures thereof in which the amino modification is effected exclusively in the side chains of a polyorganosiloxane main chain. Woven fabric surfaces are treated with the amino-modified polyorganosiloxane compounds in order to provide a use which is gentle on the skin.
Similarly, U.S. Pat. No. 6,432,270 discloses paper tissues which contain amino-modified polyorganosiloxanes having amino side chains and optionally terminal amino groups.
U.S. Pat. No. 6,030,675 discloses soft paper tissues which contain ammonium-modified polyorganosiloxanes having polyetherammonium side chains.
In the treatment of paper, transfer or migration of the softening chemicals to the user's skin is undesired. Strong binding of the softening but in particular of the hydrophilizing component is therefore desirable. Although polyethersiloxanes have a strongly hydrophilizing effect on substrate surfaces, there are no strongly binding groups with respect to paper surfaces, and moreover the more or less pronounced water solubility means that they are not very suitable since they a low substantivity.
An improved binding to the cellulose surfaces containing hydroxyl groups can be achieved, for example, by aminoalkylsiloxanes, in particular by siloxanes having tetraorgano-substituted ammonium groups, i.e. quaternized groups which are present independently of pH and can provide the bonds owing to the strong charge interaction between the negative paper fiber surface and the permanently positive charges of the quaternary ammonium groups of the silicone molecule.
WO 02/10256, WO 02/10257 and WO 02/10259 claim silicone material which permit softening of textiles during the washing process with such detergent systems. The US Published Specification 2002/0103094 discusses the use of said silicone materials in textile care formulations.
It is the object of the present invention to provide silicone compositions which have in particular good binding to the fibers (substantivity), make the paper perceptibly softer without giving rise to a significant hydrophobic character of the paper and permit easy use of the paper in the paper production process, i.e. for example are liquid.
It is furthermore the object of the present invention to provide silicone compositions which achieve further improvement with regard to the achievable softness of the treated fibers, in particular with constant or improved hydrophilic properties and substantivity (adhesion of the siloxane systems to the fibers), the flexibility of the formulation of the siloxane systems and the dosage form, in particular toward a reduction in the amounts which have to be used and in the material costs.
It is a further object of the invention to provide polysiloxane-based compositions which can be flexibly adjusted to the type of substrates to be treated and the treatment conditions by simply varying the ratios of the components present in the composition. Furthermore, the formulations should make it possible to reduce the amounts required for achieving the desired properties of the substrate to be treated and/or the use of expensive polysiloxane components, such as, for example, so-called polysiloxane quats having organofunctional groups in the α,ω-position (RfMe2SiO0.5), without there being any deterioration of the desired properties, such as softness and hydrophilic properties of the substrates to be treated.
A further object is to provide compositions which are suitable for the treatment of hard surfaces, in particular for antistatic treatment.
It was surprisingly found that a certain composition of different polysiloxane-containing compounds can achieve the above object and are economical and yet extremely effective compositions for the treatment, in particular surface treatment, of certain materials, such as, in particular, fiber materials, but also hard surfaces.